The ionosphere is the ionized part of Earth’s atmosphere, ranging from about 60 km up to several Earth radii, whereas upper above 1000 height plasmapause usually called plasmasphere. We present a new three-dimensional electron density model support space weather services and mitigate propagation errors for trans-ionospheric signals. developed by superposing Neustrelitz Plasmasphere Model (NPSM)...

The time-mean circulation in the Agulhas Retroflection area is determined by combining TOPEX/POSEIDON data and a two-layer quasi-geostrophic model using the ensemble smoother. By taking the time-mean circulation as the unknown in the data assimilation procedure, the time-varying altimeter signal is used to constrain the time-mean field. The quasi-geostrophic model is applied as a strong constra...

In the last ten years significant advances have been made in gravity field modelling, culminating in general-purpose models like JGM-3, TEG-3 and EGM96. Significant defects remain in the quality of the models when applied to orbit determination of some altimeter satellites, leading to large orbit errors, characterised by the geographically-correlated nature of the altimeter crossover height dif...

Ionospheric perturbations by natural geophysical activity, such as volcanic eruptions and earthquakes, have been studied since the great Alaskan earthquake in 1964. Measurements made from the ground show a variation of the critical frequency of the ionosphere layers before and after the shock. In this paper, we present an experimental investigation of the electron density variations around the ...

2 Abstract. A multiresolution optimal interpolation scheme is described and used to map the sea level anomaly of the Mediterranean Sea based on TOPEX/POSEIDON and ERS-1 data. The principal advantages of the multiresolution scheme are its high computational eeciency, the requirement for explicit statistical models for the oceanographic signal and the measurement errors, and the production of err...